This project builds on an ongoing funded study (OS) which compares in nonblinded fashion 100 randomly assigned parolees given psychosocial treatment (PT) and 100 randomly assigned to PT plus oral naltrexone for six months. The proposed study (PS) adds a third group of 120 randomly assigned parolees who will be treated with PT plus depot naltrexone as well as 40 additional parolees treated with PT plus oral naltrexone. The effectiveness of depot naltrexone has never been studied in parolees. All participants will be evaluated at baseline, while in treatment, and at 6- and 12-month outcome evaluations. The primary study outcomes will compare 260 subjects (140 oral naltrexone, 120 depot) with regard to attendance/retention in treatment, urine toxicologies during treatment and at follow-up, re-incarcerations, arrests, and crimes during the one year of study participation, and psychosocial functioning over the study period. It is hypothesized that depot naltrexone will result in improved outcomes vis a vis oral naltrexone. The PS will also examine whether greater criminality/antisociality, psychopathology, gender, or current alcohol abuse problem are predictive of more negative outcomes.